diff options
Diffstat (limited to 'arch/x86_64')
8 files changed, 60 insertions, 15 deletions
diff --git a/arch/x86_64/CMakeLists.txt b/arch/x86_64/CMakeLists.txt index 3c7068b..912daf6 100644 --- a/arch/x86_64/CMakeLists.txt +++ b/arch/x86_64/CMakeLists.txt @@ -91,6 +91,7 @@ target_sources("_context" PRIVATE "src/context_switching/descriptor_table/access_byte.cpp" "src/context_switching/descriptor_table/gdt_flags.cpp" "src/context_switching/descriptor_table/global_descriptor_table.cpp" + "src/context_switching/descriptor_table/global_descriptor_table_pointer.cpp" "src/context_switching/descriptor_table/segment_descriptor.cpp" ) diff --git a/arch/x86_64/include/arch/context_switching/descriptor_table/global_descriptor_table_pointer.hpp b/arch/x86_64/include/arch/context_switching/descriptor_table/global_descriptor_table_pointer.hpp index 06f40fe..ed17be3 100644 --- a/arch/x86_64/include/arch/context_switching/descriptor_table/global_descriptor_table_pointer.hpp +++ b/arch/x86_64/include/arch/context_switching/descriptor_table/global_descriptor_table_pointer.hpp @@ -18,8 +18,24 @@ namespace teachos::arch::context_switching::descriptor_table */ struct [[gnu::packed]] global_descriptor_table_pointer { - uint16_t table_length; ///< The amount of segment descriptor entries in the global descriptor table - 1. - global_descriptor_table * address; ///< Pointer to the GDT base address. + /** + * @brief Default constructor. + */ + global_descriptor_table_pointer() = default; + + /** + * @brief Constructor. + */ + global_descriptor_table_pointer(uint16_t table_length, global_descriptor_table * address); + + /** + * @brief Defaulted three-way comparsion operator. + */ + auto operator<=>(global_descriptor_table_pointer const & other) const -> std::strong_ordering = default; + + private: + uint16_t table_length = {}; ///< The amount of segment descriptor entries in the global descriptor table - 1. + global_descriptor_table * address = {}; ///< Non-owning pointer to the GDT base address. }; } // namespace teachos::arch::context_switching::descriptor_table diff --git a/arch/x86_64/include/arch/kernel/cpu/lgdt.hpp b/arch/x86_64/include/arch/kernel/cpu/lgdt.hpp index b0b2048..85e2949 100644 --- a/arch/x86_64/include/arch/kernel/cpu/lgdt.hpp +++ b/arch/x86_64/include/arch/kernel/cpu/lgdt.hpp @@ -8,6 +8,14 @@ namespace teachos::arch::kernel::cpu { + + /** + * @brief Returns the value in the GDTR register. + * + * @return Value of GDTR register. + */ + auto store_global_descriptor_table() -> context_switching::descriptor_table::global_descriptor_table_pointer; + /** * @brief Loads the global_descriptor_table_pointer into the global descriptor table register (GDTR). */ diff --git a/arch/x86_64/src/context_switching/descriptor_table/global_descriptor_table.cpp b/arch/x86_64/src/context_switching/descriptor_table/global_descriptor_table.cpp index cbd230b..c5554a7 100644 --- a/arch/x86_64/src/context_switching/descriptor_table/global_descriptor_table.cpp +++ b/arch/x86_64/src/context_switching/descriptor_table/global_descriptor_table.cpp @@ -1,6 +1,7 @@ #include "arch/context_switching/descriptor_table/global_descriptor_table.hpp" #include "arch/context_switching/descriptor_table/segment_descriptor.hpp" +#include "arch/exception_handling/assert.hpp" #include "arch/kernel/cpu/lgdt.hpp" #include "arch/stl/vector.hpp" @@ -47,6 +48,12 @@ namespace teachos::arch::context_switching::descriptor_table decltype(auto) gdt = create_global_descriptor_table(); global_descriptor_table_pointer gdt_pointer{static_cast<uint16_t>(gdt.size() - 1), &gdt}; kernel::cpu::load_global_descriptor_table(gdt_pointer); + + auto stored_gdt_pointer = kernel::cpu::store_global_descriptor_table(); + arch::exception_handling::assert( + gdt_pointer == stored_gdt_pointer, + "[Global Descriptor Table] Loaded GDTR value is not the same as the stored value."); + return gdt; } } // namespace teachos::arch::context_switching::descriptor_table diff --git a/arch/x86_64/src/context_switching/descriptor_table/global_descriptor_table_pointer.cpp b/arch/x86_64/src/context_switching/descriptor_table/global_descriptor_table_pointer.cpp new file mode 100644 index 0000000..f552496 --- /dev/null +++ b/arch/x86_64/src/context_switching/descriptor_table/global_descriptor_table_pointer.cpp @@ -0,0 +1,12 @@ +#include "arch/context_switching/descriptor_table/global_descriptor_table_pointer.hpp" + +namespace teachos::arch::context_switching::descriptor_table +{ + global_descriptor_table_pointer::global_descriptor_table_pointer(uint16_t table_length, + global_descriptor_table * address) + : table_length(table_length) + , address(address) + { + // Nothing to do. + } +} // namespace teachos::arch::context_switching::descriptor_table diff --git a/arch/x86_64/src/kernel/cpu/lgdt.cpp b/arch/x86_64/src/kernel/cpu/lgdt.cpp index cad3ffa..386914f 100644 --- a/arch/x86_64/src/kernel/cpu/lgdt.cpp +++ b/arch/x86_64/src/kernel/cpu/lgdt.cpp @@ -4,10 +4,17 @@ namespace teachos::arch::kernel::cpu { + auto store_global_descriptor_table() -> context_switching::descriptor_table::global_descriptor_table_pointer + { + context_switching::descriptor_table::global_descriptor_table_pointer current_value{}; + asm("sgdt %[output]" : [output] "=m"(current_value)); + return current_value; + } + auto load_global_descriptor_table(context_switching::descriptor_table::global_descriptor_table_pointer const & gdt_pointer) -> void { - asm volatile("lgdt %[input]" : /* no output from call */ : [input] "r"(gdt_pointer)); + asm volatile("lgdt %[input]" : /* no output from call */ : [input] "m"(gdt_pointer)); } } // namespace teachos::arch::kernel::cpu diff --git a/arch/x86_64/src/kernel/cpu/ss.cpp b/arch/x86_64/src/kernel/cpu/ss.cpp index 9c8dd61..1f28e7f 100644 --- a/arch/x86_64/src/kernel/cpu/ss.cpp +++ b/arch/x86_64/src/kernel/cpu/ss.cpp @@ -19,15 +19,15 @@ namespace teachos::arch::kernel::cpu auto read_ss() -> uint16_t { - uint16_t ss; - asm volatile("mov %%ss, %0" : "=r"(ss)); - return ss; + uint16_t segment_selector; + asm volatile("mov %%ss, %[output]" : [output] "=r"(segment_selector)); + return segment_selector; } auto write_ss(segment_selector selector) -> void { uint16_t ss = selector.to_uint16(); - asm volatile("mov %0, %%ss" ::"r"(ss)); + asm volatile("mov %[input], %%ss" : /* no output from call */ : [input] "r"(ss)); } } // namespace teachos::arch::kernel::cpu
\ No newline at end of file diff --git a/arch/x86_64/src/kernel/main.cpp b/arch/x86_64/src/kernel/main.cpp index 055b516..2c0b6c8 100644 --- a/arch/x86_64/src/kernel/main.cpp +++ b/arch/x86_64/src/kernel/main.cpp @@ -1,6 +1,7 @@ #include "arch/kernel/main.hpp" #include "arch/context_switching/descriptor_table/global_descriptor_table.hpp" +#include "arch/kernel/cpu/lgdt.hpp" #include "arch/memory/heap/bump_allocator.hpp" #include "arch/memory/heap/global_heap_allocator.hpp" #include "arch/memory/main.hpp" @@ -61,14 +62,7 @@ namespace teachos::arch::kernel heap_test(); auto global_descriptor_table = context_switching::descriptor_table::initialize_global_descriptor_table(); - - decltype(auto) x = global_descriptor_table.at(1); - if (global_descriptor_table.size() == 0) - { - } - if (x.get_segment_type() == context_switching::descriptor_table::segment_descriptor_type::CODE_SEGMENT) - { - } + (void)global_descriptor_table.at(1); video::vga::text::write("GDT FILLED", video::vga::text::common_attributes::green_on_black); } } // namespace teachos::arch::kernel |